The present invention relates to a device for parallel guiding the ram of a hydraulic press, for example, of a stamping press. For the reciprocation of the ram a drive with hydraulic cylinders is provided. The contour of the ram is substantially rectangular.
In the hydraulic presses which are known in various embodiments in the prior art the reciprocating movement of the press ram is effected with a single pressure medium cylinder or with a plurality of parallel-operating pressure medium cylinders. In all cases the parallel guiding of the stamping ram during the working movement is important. Reasons for the deviation of the parallel guiding action can be asymmetric loading and/or deviations within the operation of the parallel acting pressure medium cylinders.
When for driving the pressing ram two or more pressure medium cylinders are provided, measures must be taken which ensure an absolutely simultaneous operation of the pressure medium cylinders so that canting is prevented. Known devices for ensuring simultaneous operation for providing parallel guiding of the press ram are in general operated with a hydraulic-electronic control. Such devices are complicated and cost-intensive. Furthermore, they operate with delay because they can only be activated after at least the tendency for a beginning canting of the press ram has been detected.
The aforementioned problems are the main reason that even with hydraulic presses for relatively high working pressures it has been preferred to use a single pressure medium cylinder for driving the press ram in a fine-cutting press with high cutting precision requirements. For example, such a single pressure medium cylinder is arranged below the reciprocating press ram. In presses with very high working pressures of, for example, 10,000 kN the relatively large pressure medium cylinder must be secured in a foundation provided in a correspondingly large recess. This requires additional constructive measures during installation of such a hydraulic fine-cutting press which incur considerable expenditures.
It is therefore an object of the present invention to provide a device for parallel guiding of the press ram of a hydraulic press having simple reliable mechanical means for ensuring a reliable parallel guiding of the press ram without delay.